A brief aside, but I have quite a fondness for him: he wrote an EXCELLENT undergraduate Astronomy textbook, one of the best I’ve ever read. He’s also a science fiction fan, and was polite enough to answer one of my fan letters to him.
(You know a real nerd when he writes fan letters to textbook authors!)
Did you just say that trying to reduce Carbon emissions is a “shock” to the ecosystem?
Did you just say that we will “adapt” to changing conditions like fungi or viruses?
Well, sure! If all the animals on earth stopped exhaling CO2, the biosphere would take an immense shock!
And we’ll adapt or go extinct: Darwin is a harsh schoolmaster!
( 
)
Sigh. None of this is true. if the ‘thermostat’ was well established and well-known, the IPCC’s estimates would not range from ‘Meh’ to ‘Holy Shit’.
And of course chaotic events can change the sign. The question is, ‘do they?’, not ‘can they?’
We know they can change the sign because the climate system is relatively stable. That means that in the normal case (without CO2) the system is dominated by negative feedbacks. If feedback could not change the sign, climate would be unstable and continue to deviate in the same direction after being disturbed. Venus would be an example of that.
The real question is whether CO2 forcing will push the system out of the stable range, or what the damping factor is if we’re pushing it around in the stable range. The former would be dramatically worse, but the latter could be bad as well under the right conditions.
My contention is that we do not know enough about the behavior of this system to be able to predict it. Or rather, that our ability to predict it diminishes the further away from the baseline we get.
Nope. Didn’t say either of those things.
You know, I pointed a long time ago about many conservatives having trouble taking into account the timelines or the march of time.
There was a reason why the American Meteorological Society gave a medal to Hansen, it was because even if he missed in some estimates his conclusions were valid, and he has helped in the progress seen nowadays. The problem with your insistence of “going away from the baseline” is that we are now getting close to that, and the observations are closer to what scientists predicted than what contrarians told us it was going to happen. Right now we are observing an acceleration of the loss of cap ice, we are observing the increase in water vapor in some regions and an increase of energy, and many more observations of things and feedbacks that were expected with an increase in the temperature.
And one more thing about continuing to insist that “we do not know enough” or that we cannot predict the behavior of a chaotic system; we can not be exact, but a lot of what can be expected can be deduced. And what it is maddening to contrarians is that scientists have managed to get very close to deduce the general behavior of the system, regardless of how complex it is. They have indeed done what many deniers continue to insist it is not possible, regardless of the evidence that the tools used by climate scientists do work on earth and in other planets.
[QUOTE=Mork and Mindy]
Psychologist: “Your Honor, yesterday, during one of my tests, he tried to put a SQUARE peg, into a ROUND hole!”
Mork: “But I did it, your honor!”
Psychologist: I do not now how but he did!
[/QUOTE]
Climate scientists and economists that are involved in the issue are not just throwing their hands in the air just because of the complexity, there is already evidence of what models and other tools are capable of. And there are already observations that point to the environment changing because of the increase of global warming gases. Continuing to point at very exaggerated uncertainty monsters is ignoring an important part of the science that it is already well understood.
You continue to speak about feedbacks that can counter what many experts expect. Problem is that when nature did toss a lot of CO2 in to the atmosphere in the Pliocene all those natural negative feedbacks you want to see coming forward did not stop the planet from getting warmer, the super molds were not effective either.
So, really, your proposed feedbacks are still just wishful thinking. And with little evidence that they would be decisive in saving us by serendipity. No, the advice from the experts that we should control our emissions ASAP cannot be avoided.
Sam, that’s just wrong – pretty much all of it – and not only is it wrong, it’s wrong at a pretty basic level. The statement by Budget Player Cadet that CO2 (or, more precisely, atmospheric carbon) is the thermostat of the planet captures the idea correctly.
The basic operative fact here is what I said earlier, that your argument about the behavior of complex adaptive systems is irrelevant because a persistent forcing over a sufficiently long period will always eventually unbalance the system and drive it in the direction of the forcing. The simplest analogy familiar to us all is the seasons. The weather is the classic example of a complex system – indeed that’s where chaos theory comes from. And I’ve just been observing it: it was so cold a few days ago that I thought about turning on the heat, and today, later into the fall, it was so hot that I had the A/C on. Yet I know that it will get colder as winter approaches, and you know it, too – chaos or no chaos. I just don’t know exactly when, or what the precise pattern will be. But at some point the furnace will come on and the snow will fall. And this will happen – predictably and without any doubt – because the total amount of solar insolation in my part of the world is steadily decreasing.
The only question with respect to climate is how well we understand what the requisite magnitude and duration of such forcings must be in order to drive long-term global changes. As it turns out, we understand it pretty well. A lot of what we understand comes from work in paleoclimatology.
Among the most significant facts about climate sensitivity in the present quaternary epoch is the relatively consistent band of CO2 fluctuations between ice ages, around 180 ppm at peak glaciation to around 280-300 ppm at the peak of interglacials, which is where we should be now. IOW, 100 ppm of CO2 is the difference between nice balmy North American summers and North America being under a mile-thick sheet of ice. Yet we have added more than that – about 115 ppm – to the atmosphere in the post-industrial era. Talking about magical feedbacks and chaos theory in light of such a sustained forcing over centennial timescales and beyond is just ludicrous. This is where the deniers turn to nonsensical babble about GHG forcings being somehow magically self-limiting, which is a terrific theory except that (a) it has no theoretical basis, and (b) it’s never been observed in the paleoclimate record.
Another interesting case study from paleoclimatology is the Paleocene-Eocene Thermal Maximum, where vast amounts of carbon were released into the atmosphere, possibly from undersea biomass, in a series of events that somewhat parallel the rate of change of present AGW. The temperature soared and the results were catastrophic for the planetary biosphere.
You go on to make a series of statements to back up your argument and all of them are wrong. You say “if the ‘thermostat’ was well established and well-known, the IPCC’s estimates would not range from ‘Meh’ to ‘Holy Shit’”. But they are established enough that climate sensitivity is pretty reliably pegged at between 1.5 and 4.5°C (and so tightly bounded at the lower end that the model medians are all towards the higher end). Yes, a wide range, but a meaningful one. And there has never been a lower bound that was negative!
Yoy say “of course chaotic events can change the sign”. Only over sufficiently short timeframes. See everything I just said above.
Now let me focus on this specific fallacy:
The climate system is stable because net positive feedbacks are eventually balanced by increased radiative flux to space. For instance, water vapor feedback, as strong as it is, is only about half as much as the earth’s blackbody effect contributes to cooling, otherwise we would indeed have runaway climate change from that feedback alone.
But this is just saying that a hotter body predictably and systematically radiates more, and it’s misleading to characterize this as “the system is dominated by negative feedbacks”. The climate system, in fact, is dominated by net positive feedbacks – and that’s precisely what the equilibrium climate sensitivity I mentioned before is measuring. They are things like increases in water vapor with temperature, reduced polar albedo due to reduced ice cover, and hundreds of other things. Relatively few feedbacks are negative. That’s why climate sensitivity has the values that it does.
One more thing. Somewhere you implied the possible existence of some imaginary “long-term feedback” that might magically put an end to warming. This is not just pure nonsense but the opposite of the reality. The long-term feedbacks are dominated by the complete loss of polar ice. If that ever happens you can at least double or triple the climate sensitivity factor. It would send us back to the Eocene epoch and drive the oceans hundreds of feet higher and pretty much end civilization as we know it. And again, we understand these behaviors from paleoclimatology, both long-term geologic-scale changes and relatively shorter-term changes like ice age transitions and the Paleocene-Eocene event, and increasingly accurately from modeling.
Another thing that should not be overlooked is that sustained climate change is also characterized by so-called tipping points, where a prolonged period of incremental change leads to sudden and extreme changes in the pattern of the global climate, generally due to major circulation systems being driven to the point of disruption. This aspect of climate behavior was one of the major discoveries of the respected climatologist Hans Oeschger, and one such pattern of abrupt climate changes are called Dansgaard-Oeschger events in his honor. His discoveries led him to become deeply concerned about what man was doing to this planet.
I just noticed this, and I think it’s worth a comment since there’s an important object lesson here.
But your statement was “[rainforest growth] changes a large positive feedback into a large negative one, as rainforest growth would increase on a warmer planet.”
Your cite does not support that statement. In fact that statement has no scientific basis. The article suggests the possibility but mostly emphasizes the uncertainties. As with all prognostications about supposedly beneficial effects of warming, the benefits may be short-lived or they may not happen at all. In many specific instances, like the rainforest case, we just don’t know, but in general the evidence is overwhelming that in the aggregate the negatives will outweigh the positives, as in the impacts chart that I linked upthread.
In the specific case of the rainforest, there is, for example, evidence of a longer dry season in the southern Amazon. There are corroborating studies for increasing risk of drought in the Amazon basin. There’s even a study suggesting that reductions in atmospheric aerosols could precipitate Amazonian drought. On top of all that ongoing massive deforestation and increased fire risk could negate the effects of CO2 fertilization even if it did occur.
And even if it all happened with the most optimistic possible outcome, all it would do is marginally lower the retained atmospheric CO2, and only as long as the increased carbon uptake was operative. Which may not be very long. These effects have been studied to some degree with experiments like FACE (Free Air CO2 Enrichment) with less than stellar outcomes. One consideration is that CO2-enriched vegetation quickly hits other limits, like soil nutrients. And one unanticipated odd impact, pertaining to crops, is that under CO2 enrichment quality may suffer.
The CO2 uptake of the terrestrial biosphere is clearly something that we need to understand and be able to model accurately, but like a million other such factors, no one has ever suggested that any increased CO2 uptake, even if it occurs, fundamentally changes the AGW problem or the need to mitigate emissions.
So the unqualified claim you made has no scientific support whatsoever.
Thank you for putting this far better than I could. I’d also go a little further and say that if you don’t understand this basic factor by this point, you really should do more reading before getting into the subject. I’m no expert, but even I get this. As we add more CO2 to the atmosphere, more heat is trapped. In the long term, the chaotic events tend to even out, leaving us with the signal. You know, that other thing in “The Signal and the Noise”.
"That’s an example of how sophisticated adaptive systems can be, even at the simplest levels. Imagine a globe full of them all through the ecosystem. To believe that we can predict what’s it’s going to be like 100 years from now **after we apply a shock to it **takes a real leap of faith.
By the way, when those slime molds start to dry up, they have another trick up their sleeve. Their behavior changes entirely and they start to grow ‘pods’ full of spores, then they sacrifice themselves to elevate the pods to the point where the wind can catch them. They fly away over long distances, then the pods break open and disgorge the spores, spreading the slime molds to new regions where there is more moisture. There they eat decaying vegetation. So nature has evolved a creature that moves from area to area feeding on dead vegetation. That’s yet another feedback - if climate change causes an area to dry, slime molds will suddenly lift off and fly around, descending on other ecosystems and changing them. Other animals that eat the same decaying vegetation have their own complex responses, and so it goes."
Since I never used the word “contradicts”, that would be logical. I did repeat a direct quote, which is, “but they do change our fundamental understanding of how that warming comes about”. Since the topic is actually about trust and science and “why won’t somebody just explain it and show the evidence”, it directly speaks to the issue of trust and science.
Clearly he was talking about a “shock” to the system being the shock of sudden and drastic global warming, not reducing our carbon output.
And the adaptation was about how nature adapts, and how unpredictable it all is. Sort of like how you can never predict what somebody will read into any commentary you leave on the internet.
Nature can adapt without humans. He may not have meant to say it but he did. We may very well put ourselves out of business, and the universe will be just fine. Because we can’t “predict” anything.
The feedbacks associated with climate change are complicated. I admit to being very confused about the feedbacks – both negative and positive – associated with water vapor. (Though I’m not so confused as to seek answers from non-specialist anti-AGW bloggers. 
)
On the matter of feedback mechanisms associated with carbon accumulation in rainforests there seem to be several unrelated issues:
[ul][li] All other things being equal, how does higher CO2 affect forest growth per acre?[/li][li] Independent of CO2 levels, how does climate change affect forest growth? (The Amazon forest is expected to suffer as rainfall reduces in response to climate change. And of course, there is positive feedback here, as much rainforest rain is caused by the forest!)[/li][li] Human intervention to encourage or discourage forestation.[/li][/ul]
The final item is the big “elephant in the room” of course. Forests are disappearing at a net rate of perhaps 2,000 acres per hour or more. One of the first threads I started as a Doper was on this and related topics.
And, if a shift in rain patterns means rainforest “needs” to move from Brazil to some part of Africa, it’s doubtful that the people there would permit new forest to encroach.
I’m glad you posted a cite for this, Sam. I found that paper to be written in a very confusing way, but they do seem to focus only on the first item in the above list, as acknowledged even in their Abstract, which you quoted:
Moreover, even that first item seems to be controversial:
In summary, hoping for rainforest growth to counteract CO2 warming seems to be fanciful wishful thinking.
[QUOTE=Sam Stone]
A simple example of a nonlinear system is a pile of sand. Start dropping sand on the pile, and try to predict what the height of the pile will be with each new grain. Good luck.
[/QUOTE]
I think you’ve picked an unusually poor example to make your point! The sand-pile is an oft-used example describing how stability and predictability arise despite nonlinearities and chaos. Cites for this are so plentiful I’ll offer an obscure one relating sandpiles to brain behavior!
This is an example of the sort of thing that both confuses and creates skepticism, especially among those educated about the issues.
First, rather than answer a scientific question, or set of questions, important questions, it’s a claim about “hope”, and “wishful thinking”, with an unsupported conclusion of some sort.
While in the real world scientist and researchers are doing, and have done, a lot of actual research, and experiments in regards to the issue of both increased CO2, and increasing temperatures. For a very long time now.
Looking at any actual research paper on this will show a huge, just huge long list of references on the matter.
Effect of CO2-enrichnient on seedling physiology and growth of two tropical tree species
There are papers claiming increased CO2/temperatures might unbalance species (while admitting all species increased growth and reduced the need for water), as well as experiments to see if that is true. (it’s not true, at least as far as we can tell)
Old papers
And older ones
even older
In fact, the abundance of studies and actual experiments on this issue, makes it seem extremely odd that anyone would have the impression it’s “an unknown”, or “it’s probably going to be bad”, or that we don’t know much about tropical forests and conditions. Which is complete bullshit.
Since all the research replicates exactly what plant specialist already knew about plants, and especially tropical ones. More CO2 (like, up to 2000 ppm) and warmer night time temperatures increases growth. A lot. It also allows plants to need less water.
What you will get from a lot of biased sources is this speculation and “maybes” that always, always try and put a negative spin on it all. Every last bit of the positive news from actual experiments is spun to somehow be a bad thing. Which brings us back to the topic at hand.
Why would something like the tropical forest response be such a contentious issue? And seemingly such a mystery? A subject of “unknowns” and mights and maybes?
You would think something this important would be clearly explained, with sources and everything.
Right?
I mean, that is the topic (not yet another argument over every last thing related to climate and global warming)
Indeed, but it has happened, even in this thread and before that more detailed explanations and links to papers like the one Plass made are willfully ignored by contrarians, and so we get the odd posts were contrarians still claim that nothing was explained many times before.
The big problem that one can see coming by the denier propaganda out there is that it does even influence scientists into adopting the framework that deniers use. The purpose is simple, to confuse the issue and to make it sound like if there is a controversy among scientists were there is very little in reality. A very good example was to press the point that people like Polar researchers like Judah Cohen and Jenifer Francis have a new theory for the cause of the harsh winters in northern latitudes.
Contrarians continue to claim that theories like that dismiss the global warming gases one and the effects observed. Never mind that Cohen and Francis reported that they do use the previous theories to explain the odd extreme winter conditions in areas of the northern hemisphere. Even those scientists are not dismissing the warming caused by CO2 and other global warming gases, but that fact seems to enter one ear and leave from the other among many deniers out there.
Another example was seen by getting scientists to talk about a hiatus in the global surface temperature record when many do and did point that to talk about a hiatus while the oceans were warming at the same time was ignoring the natural noise that is in the system.
(And yes, many references at the bottom)
The result is what we see: policy makers, specially in America, that fall pray to nonsense like “The Hockey stick is an abortion of science” or that “there has been no warming in the past x years”.